US3745768A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus to control the proportion of air and fuel in the air fuel mixture of internal combustion engines
Assignee: Robert Bosch GmbH
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Filing: 1972-03-30
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Granted: 1973-07-17
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Expires: 1992-03-30
Abstract
Abstract An oxygen analyzer responsive to oxygen partial pressure and comprising an oxygen ion conductive solid electrolyte is exposed to the exhaust gases of an internal combustion engine. The sensed value is applied to a low pass filter which is interconnected in an electrical circuit to control the amount of fuel being admitted, relative to the amount of air, so that the air-fuel ratio of the air-fuel mixture can be maintained at a predetermined level. In one embodiment, the mixture is regulated to provide a minimum of unburnt hydrocarbon and carbon monoxide in the exhaust, the remaining noxious exhaust gases formed primarily of nitrogen compounds being neutralized by a catalytic converter, so that the catalytic converter need have only single bed neutralizing only one substantial noxious exhaust component. Control of the amount of fuel can be obtained either by controlling the amount of fuel injected in an injection system, or controlling an additional air path. Sensing of other parameters, such as CO, temperature, and the like, may also be provided.
Inventors
- 👤 J Wahl
- 👤 R Zechnall
- 👤 P Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:33
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1438; F02D41/1477; F02D41/1479; F02D35/00; F02D35/0015; F02D35/0023; F02D35/003; F02D41/1439; F02D41/1441; F02D41/1444; F02D41/1446; F02D41/1486; F02D41/1488; F02D41/149; F02M; F02M23/00; F02M23/04; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12; Y02T10/40
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
152 words
Apparatus to control the ratio of air to fuel of the air-fuel mixture being applied to an internal combustion engine comprising oxygen analyzer means (21) responsive to oxygen partial pressure in the exhaust gas and having an oxygen ion conductive solid electrolyte, said analyzer means being located on contact with the exhaust gases from said engine and providing an electrical output signal; an electrical control circuit controlling the amount of at least one of the fuel and the air of the air-fuel mixture being applied to the engine; a low pass filter (22) interconnected in circuit between the output of the oxygen partial pressure analyzing means and the electronic control circuit; a threshold circuit (23) connected in series between the low pass filter and the control circuit, the threshold response of the threshold circuit (23) being set to respond to the voltage jumps (FIG. 7: U1, U2) of the oxygen analyzer means.
Claim 2
Dependent Claim
152 words
Apparatus to control the ratio of air to fuel of the air-fuel mixture being applied to an internal combustion engine comprising oxygen analyzer means (21) responsive to oxygen partial pressure in the exhaust gas and having an oxygen ion conductive solid electrolyte, said analyzer means being located on contact with the exhaust gases from said engine and providing an electrical output signal; an electrical control circuit controlling the amount of at least one of the fuel and the air of the air-fuel mixture being applied to the engine; a low pass filter (22) interconnected in circuit between the output of the oxygen partial pressure analyzing means and the electronic control circuit; a threshold circuit (23) connected in series between the low pass filter and the control circuit, the threshold response of the threshold circuit (23) being set to respond to the voltage jumps (FIG. 7: U1, U2) of the oxygen analyzer means.
Claim 3
Dependent Claim
50 words
Apparatus according to claim 1, wherein the control circuit includes a control multivibrator (MV) (30); a fuel injection system (27, 28) is provided injecting fuel under control of the switching rate of the control MV (30), the output of the low pass filter (23) being applied to the control MV.
Claim 4
Dependent Claim
28 words
Apparatus according to claim 2, further comprising a limiter circuit (25) limiting the output of the threshold circuit (23), the limited signal being applied to the control circuit.
Claim 5
Dependent Claim
36 words
Apparatus according to claim 1, further comprising (FIG. 1) a feedback circuit (24) including a feedback low pass filter interconnecting the output of the threshold circuit (23) and the input to the low pass filter (22).
Claim 6
Dependent Claim
115 words
Apparatus according to claim 1, wherein (FIG. 2) the control circuit includes a control multivibrator (30) and a multiplier stage (40) connEcted thereto, and a fuel injection system is provided injecting fuel under control of pulses derived from the control multivibrator, and as multiplied in the multiplier circuit, the apparatus further comprising a pair of differential amplifiers (35, 36) connected to the output of the low pass filter (22); one of the differential amplifiers (35) being connected to an input (314) of the control multivibrator (30) and the other differential amplifier (36) being connected to an input of the multiplier stage (40) connected between the output of the control multivibrator and the fuel injection system.
Claim 7
Dependent Claim
63 words
Apparatus according to claim 5, wherein the inverting input of the first differential amplifier (35) and the non-inverting input of the second differential amplifier (36) are connected to the output of the low pass filter (22); and a reference source (37) is connected to the non-inverting input of the first differential amplifier and to the inverting input of the second differential amplifier (36).
Claim 8
Dependent Claim
27 words
Apparatus according to claim 6, wherein the reference source (37) provides an output voltage which is above the upper voltage level (U1) of the oxygen analyzer (21).
Claim 9
Dependent Claim
43 words
Apparatus according to claim 1, wherein the internal combustion engine has an auxiliary air supply (51) and means (50) controlling the amount of auxiliary air being supplied to the engine; the electronic control circuit controlling the position of the additional air supply means.
Claim 10
Dependent Claim
32 words
Apparatus according to claim 8, wherein the electronic control circuit comprises a differential amplifier (45) interconnecting the output of the low pass filter (22) and the additional air supply control means (50).
Claim 11
Dependent Claim
19 words
Apparatus according to claim 9, wherein the differential amplifier has one input connected to an adjustable reference source (46).
Claim 12
Dependent Claim
53 words
Apparatus according to claim 1, further comprising carbon monoxide (CO) sensing means (56) located to sense the CO content of the exhaust from the internal combustion engine; and circuit means connected with said electronic circuit controlling the relationship between air and fuel of the air-fuel mixture being applied to the internal combustion engine.
Claim 13
Dependent Claim
23 words
Apparatus according to claim 11, including an additional low pass filter (57) interconnected between the CO sensing means and the electronic control circuit.
Claim 14
Dependent Claim
37 words
Apparatus according to claim 1, further comprising temperature sensing means located to sense temperature levels of the exhaust gases and an additional low pass filter (57) interconnected between said temperature sensing means and the electronic control circuit.
Claim 15
Dependent Claim
65 words
Apparatus according to claim 5, further comprising a CO sensing means (56) and a second low pass filter (57) connected thereto; a second pair of differential amplifiers (58, 59) connected to the output of the second low pass filter (57); and means (62, 63) selectively interconnecting the first pair (35, 36) or the second pair (58, 59) of differential amplifiers with the electronic control circuit.
Claim 16
Dependent Claim
22 words
Apparatus according to claim 14, further comprising a function generator (70) interconnected with and providing a reference voltage to said differential amplifiers.
Claim 17
Dependent Claim
67 words
Apparatus according to claim 15, wherein the function generator (70) has a first control input (707) having a signal applied thereto depending on engine speed and a second control input (717) having a signal applied thereto dependent on the position of the fuel control for the engine, the function generator providing an ouput reference potential depending on engine operating characteristics at given speed and fuel controller positions.
Claim 18
Dependent Claim
67 words
Apparatus according to claim 16, comprising a first input threshold switch (700) connected to the first control input of the function generator (70); a second input threshold switch (710) connected to the output of the first input threshold switch (700) and further connected to the second control input (717) to set the threShold level of an input signal which has been applied to said second control input.
Claim 19
Dependent Claim
46 words
Apparatus according to claim 16, including an idle switch (725) interconnected with the fuel controller of the engine and controlling the function generator to provide a fixed reference output signal to the second pair of differential amplifiers (58, 59) connected to the CO sensing means (56).
Claim 20
Dependent Claim
69 words
Apparatus according to claim 17, comprising an idle switch (725) interconnected with the fuel controller of the engine; a switching transistor (740), the output of which forms the first output (745) of the function generator, the idle switch (725) and the second threshold switch (710) controlling said switching transistor; the first output (745) of the function generator (70) controlling the switching state of said selective interconnection means (62, 63).
Claim 21
Dependent Claim
60 words
Apparatus according to claim 18, comprising an operational amplifier (730) interconnected with the output of said idle switch (725) and the second threshold switch (710), the output of the operational amplifier forming the second output (737) of the function generator (70), said output being connected to and providing a reference potential to the second pair of differential amplifiers (58, 59).
Claim 22
Dependent Claim
46 words
Apparatus according to claim 14, wherein the function generator (70) comprises a voltage source (55, 54; 750, 751) forming a third output (755) of the function generator (70) and being connected to and providing a reference voltage to the first pair of differential amplifiers (38, 39).
Claim 23
Dependent Claim
56 words
Apparatus according to claim 1, including a thermo element (80) in heat sensing relation to the exhaust gases from the internal combustion engine; and means (81, 83) interconnecting the output of the low pass filter (22) and the output of the thermo element (80) and applying said outputs to the input of the electronic control circuit.
Claim 24
Dependent Claim
78 words
Apparatus according to claim 22 (FIG. 9) wherein the interconnecting means interconnecting the output of the low pass filter (22) and the output of the thermo element (80) comprises a differential amplifier (81) connected to the thermo element; a control amplifier (83) interconnecting the output of the differential amplifier (81) and the low pass filter; and means including signal limiting means (84) interconnecting the output of the control amplifier and an input (314) of the electronic circuit (30).
Claim 25
Dependent Claim
59 words
Apparatus according to claim 23, further comprising means sensing (82) an output limit of the thermo element (80); a change-over switch (86) controlled by the output sensing means (82); a source of reference voltage (87, 88); said change-over switch (86) selectively interconnecting the reference voltage (87, 88) or the output of said control amplifier (83) to the electronic circuit.
Claim 26
Dependent Claim
35 words
Apparatus according to claim 1, comprising an exhaust gas reactor (69) located to have the exhaust gases from the internal combustion engine applied thereto, said exhaust gas reactor being of the single catalyst bed type.
Claim 27
Dependent Claim
165 words
Method of controlling the air to fuel ratio of the air component and the fuel component of the mixture being applied to an internal combustion engine comprising analyzing the exhaust gas for oxygen partial pressure and deriving a sensed electrical signal representative of this analysis; removing higher frequency components in the output variations of the sensed signal by filtering the sensed signal in a low pass filter and deriving a modified sensed signal; controlling, under command of said modified sensed signal, the admission of at least one of the components of the mixture to control the ratio of said fuel and air components in the fuel-air mixture to provide an excess of air to obtain exhaust gases from the engine having only a single substantial remaining noxious component resulting from said excess of air; and the method comprises the further step of passing the exhaust over a reactor responsive to said siNgle noxious component to remove said single substantial remaining noxious component from the exhaust.
Claim 28
Dependent Claim
165 words
Method of controlling the air to fuel ratio of the air component and the fuel component of the mixture being applied to an internal combustion engine comprising analyzing the exhaust gas for oxygen partial pressure and deriving a sensed electrical signal representative of this analysis; removing higher frequency components in the output variations of the sensed signal by filtering the sensed signal in a low pass filter and deriving a modified sensed signal; controlling, under command of said modified sensed signal, the admission of at least one of the components of the mixture to control the ratio of said fuel and air components in the fuel-air mixture to provide an excess of air to obtain exhaust gases from the engine having only a single substantial remaining noxious component resulting from said excess of air; and the method comprises the further step of passing the exhaust over a reactor responsive to said siNgle noxious component to remove said single substantial remaining noxious component from the exhaust.
Claim 29
Dependent Claim
49 words
Method according to claim 26, comprising the step of sensing an operating parameter of the engine; and modifying the command transfer function of the modified sensed signal with respect to control of the ratio of components of the mixture in dependence on a sensed operating parameter of the engine.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-16 | 1977-01-15 | 1977-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-16 | 1981-01-15 | 1981-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-16 | 1985-01-15 | 1985-07-17 | $7700.00 | Window Closed / Lapsed |